CN108463475A - （Methyl）Acrylic ester polymer - Google Patents

Abstract

The molecular weight distribution that there is provided high molecular weight side is small, can obtain (methyl) acrylic ester polymer for the lubricating oil that shear viscosity has good stability.A kind of (methyl) acrylic ester polymer (A), it contains specific structural unit, wherein, it is standardized as in the 1 differential molecular weight distribution curve of polystyrene conversion molecular weight in the intensity for measuring peak top molecular weight M (t) obtain, polystyrene conversion by gel permeation chromatography (GPC) of (methyl) acrylic ester polymer (A), the polystyrene conversion molecular weight in the high molecular weight side for the position for being 0.5 by intensity is set as M_h(t_1/2) when, a=LogM_h(t_1/2) a values represented by LogM (t) are 0.12 or less.

Description

(meth)acrylate polymer

technical field

The present invention relates to a (meth)acrylate polymer having a small molecular weight distribution on the high molecular weight side. The (meth)acrylate polymer is useful as a viscosity index improver for lubricating oil, for example.

Background technique

As a viscosity index improver added to improve the fuel consumption performance of lubricating oils used in internal combustion engines such as automobile engines, transmissions, etc., narrowly dispersed (meth)acrylate polymers with a small Mw/Mn (for example, Refer to Patent Documents 1 to 3).

Examples of methods for producing such narrowly dispersed (meth)acrylate polymers include atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT), nitroxide-mediated polymerization (NMP), Boron-mediated polymerization, catalytic chain transfer polymerization (CCT) and the like (for example, refer to Patent Documents 4 to 6). Moreover, as a useful production method, anionic polymerization (representatively highly active anionic polymerization) is mentioned (for example, refer patent document 7). Narrowly dispersed (meth)acrylate polymers can be obtained by these production methods, but (meth)acrylate polymers capable of obtaining lubricating oils with high shear viscosity stability are required.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2015-013957

Patent Document 2: Japanese Patent Laid-Open No. 2015-013962

Patent Document 3: International Publication No. 2014/017554

Patent Document 4: Japanese PCT Publication No. 2003-515630

Patent Document 5: Japanese PCT Publication No. 2008-518051

Patent Document 6: Japanese PCT Publication No. 2007-512413

Patent Document 7: Japanese Patent Laid-Open No. 2007-084658

Contents of the invention

The problem to be solved by the invention

An object of the present invention is to provide a (meth)acrylate polymer that has a small molecular weight distribution on the high molecular weight side and can obtain a lubricating oil with good shear viscosity stability.

method used to solve the problem

As a result of studies to achieve the above objects, the present invention including the following aspects has been accomplished.

[1] A (meth)acrylate polymer (A) containing a structural unit represented by the following general formula (1), wherein in the (meth)acrylate polymer (A) In the differential molecular weight distribution curve of the polystyrene-equivalent molecular weight obtained by gel permeation chromatography (GPC) measurement, the intensity of the polystyrene-equivalent peak top molecular weight M(t) was normalized to 1, when the intensity was set to 0.5 When the polystyrene-equivalent molecular weight on the high molecular weight side of the position is M _h (t _1/2 ), the value of a represented by the following formula (2) is 0.12 or less.

(In formula (1), ^R1 represents a hydrogen atom or a methyl group, and ^R2 represents an alkyl group having 10 to 36 carbon atoms.)

a＝LogM _h (t _1/2 )-LogM(t) (2)

[2] The (meth)acrylate polymer (A) according to [1], wherein, in the differential molecular weight distribution curve described in [1], polyphenylene on the low molecular weight side of the position where the intensity is 0.5 When the molecular weight in terms of ethylene is M _l (t _1/2 ), the half width LogM _h (t _1/2 )-LogM _l (t _1/2 ) is 0.3 or less.

[3] The (meth)acrylate polymer (A) according to [1] or [2], wherein the structural unit represented by the above general formula (1) is The mass content of all the structural units of (A) is 40-80 mass %.

[4] The (meth)acrylate polymer (A) according to any one of [1] to [3], wherein the polystyrene-equivalent weight average molecular weight calculated by the GPC measurement described in [1] is Mw is 50,000 to 500,000.

[5] The method for producing the (meth)acrylate polymer (A) according to any one of [1] to [4], which utilizes an anionic polymerization method in the presence of an organoaluminum compound.

Invention effect

According to the present invention, a (meth)acrylate polymer having a small molecular weight distribution on the high molecular weight side and a lubricating oil having good shear viscosity stability can be obtained.

Description of drawings

Fig. 1 shows M(t), M _h (t _1/2 ), M _l (t _1/2 ), a value, half Summary plot of peak widths.

Detailed ways

The present invention will be described in detail below. It should be noted that, in this specification, "(meth)acryloyl" is the general term for "methacryloyl" and "acryloyl", and "(meth)acrylate" is "methacrylate" and " Acrylate" general term.

The narrow molecular weight distribution on the high molecular weight side of the (meth)acrylate polymer (A) of the present invention is important from the viewpoint of not only narrowing the molecular weight distribution but also obtaining a lubricating oil exhibiting high shear viscosity stability. of. As a method of evaluating the molecular weight distribution on the high molecular weight side, the following method was used.

A chromatogram obtained by gel permeation chromatography (GPC) measurement was converted into a differential molecular weight distribution curve of polystyrene-equivalent molecular weight using a calibration curve showing the relationship between the elution time and the molecular weight of standard polystyrene. At this time, the measurement intensity at the polystyrene-equivalent peak top molecular weight (molecular weight with the highest measurement intensity) M(t) of the (meth)acrylate-based polymer (A) was normalized to 1.

In the differential molecular weight distribution curve obtained in this way, when the polystyrene-equivalent molecular weight on the high molecular weight side at the position where the strength is 0.5 is M _h (t _1/2 ), the value of a represented by the following formula (2) The (meth)acrylate polymer (A) which is 0.12 or less (see FIG. 1 ) can be called a polymer with a small molecular weight distribution on the high molecular weight side. The a value is an indicator of the molecular weight distribution of a high molecular weight body having a higher molecular weight than the peak top molecular weight of the (meth)acrylate polymer (A), and the smaller the value, the higher the molecular weight of the (meth)acrylate polymer (A). The molecular weight distribution of the contained high molecular weight components is narrower.

a＝Log M _h (t _1/2 )-Log M(t) (2)

From the viewpoint of obtaining a (meth)acrylate polymer having good shear viscosity stability, the a value is preferably 0.11 or less, more preferably 0.10 or less, and even more preferably 0.095 or less. It should be noted that, in the above formula (2), Log represents a common logarithm (logarithm with base 10). In addition, the above-mentioned a value is usually 0.05 or more.

In the above-mentioned (meth)acrylate polymer (A), when the polystyrene-equivalent molecular weight on the low molecular weight side at the position where the intensity is 0.5 is M ₁ (t _1/2 ), it is preferable that the half-width LogM _h (t _1/2 )-LogM _l (t _1/2 ) is 0.3 or less. When the half width is 0.3 or less, it can be said that the molecular weight distribution on the low molecular weight side is also narrow, and the amount of the polymer having a molecular weight smaller than M(t) is also small. When such a (meth)acrylate polymer (A) is used for applications such as a viscosity index improver, the ratio of polymers that do not contribute to improvement of the viscosity index is small, and the amount of addition can be reduced. From this point of view, the aforementioned half width is preferably 0.3 or less, more preferably 0.25 or less. In addition, the said half width is usually 0.1 or more.

In addition, shear viscosity stability can be evaluated by shear stability index (SSI), for example. SSI is a measure of the loss of kinematic viscosity due to the shear force and molecular chain cutting of the polymer component in the lubricating oil, and the larger the value of SSI, the greater the loss of kinematic viscosity. The SSI is an index representing the decrease in viscosity due to shearing from the polymer component as a percentage, and can be calculated by the following calculation formula.

In the above formula, Kv ₀ is a value of the 100° C. kinematic viscosity of a mixture obtained by adding a (meth)acrylate polymer to a base oil constituting a lubricating oil. Kv ₁ is the value of the kinematic viscosity at 100° C. after applying shear to a mixture obtained by adding a (meth)acrylate polymer to a base oil constituting a lubricating oil according to the procedure of ASTM D6278. In addition, Kv _oil is a value of the 100 degreeC kinematic viscosity of the base oil which comprises a lubricating oil.

The value of the SSI is preferably low, specifically, preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, still more preferably 5% or less, most preferably 2% or less.

The (meth)acrylate polymer of this invention is a (meth)acrylate polymer (A) containing the structural unit represented by following General formula (1). The (meth)acrylate polymer (A) can be obtained, for example, by polymerizing a (meth)acrylate polymerizable monomer, and the (meth)acrylate polymerizable monomer contains the following Alkyl (meth)acrylate which has an alkyl group of the structural unit represented by General formula (1).

(In formula (1), ^R1 represents a hydrogen atom or a methyl group, and ^R2 represents an alkyl group having 10 to 36 carbon atoms.)

〔(Meth)acrylate polymerizable monomer〕

Examples of the alkyl (meth)acrylate having an alkyl group serving as the structural unit represented by the general formula (1) include alkyl (meth)acrylates having an alkyl group having 10 to 36 carbon atoms. Examples of the alkyl (meth)acrylate include n-decyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, ( n-tridecyl methacrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, n-hexadecyl (meth)acrylate, (meth)acrylate ) n-heptadecyl acrylate, n-octadecyl (meth)acrylate, n-nonadecyl (meth)acrylate, n-eicosyl (meth)acrylate, (meth)acrylic acid n-behenyl ester, n-behenyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, (meth)acrylic acid ) n-pentacyl acrylate, n-hexacyl (meth)acrylate, n-heptacyl (meth)acrylate, n-octadecyl (meth)acrylate, ( n-Nacodecyl Methacrylate, n-Triadecyl (Meth)acrylate, n-Triaconyl (Meth)acrylate, n-Docosyl (Meth)acrylate, Tridecyl (meth)acrylate, Tritetradecyl (meth)acrylate, Tripentacyl (meth)acrylate, Hexadecyl (meth)acrylate Alkyl (meth)acrylates containing linear alkyl groups such as esters; isodecyl (meth)acrylate, 2,4,6-trimethylheptyl (meth)acrylate, 2-(meth)acrylate Butyl octyl ester, 2-ethyl-n-dodecyl (meth)acrylate, 2-methyl-n-tetradecyl (meth)acrylate, isohexadecyl (meth)acrylate , 2-n-octyl-n-nonyl (meth)acrylate, isostearyl (meth)acrylate, 1-n-hexyl-n-tridecyl (meth)acrylate, (meth)acrylic acid 2-Ethyl-n-heptadecyl ester, isoeicosyl (meth)acrylate, 1-n-octyl-n-pentadecyl (meth)acrylate, 2-n-pentadecyl (meth)acrylate Decyl-n-tetradecyl ester, 2-n-dodecyl-n-pentadecyl (meth)acrylate, isotridecyl (meth)acrylate, 2-n-pentadecyl (meth)acrylate Tetradecyl-n-heptadecyl ester, 2-n-hexadecyl-n-heptadecyl (meth)acrylate, 2-n-hexadecyl-n-eicosyl (meth)acrylate and alkyl (meth)acrylates containing branched alkyl groups such as 2-n-tetradecyl-n-behenyl (meth)acrylate; etc.

As the above-mentioned alkyl (meth)acrylate having an alkyl group having 10 to 36 carbon atoms, it is preferable to have an alkyl group having 10 to 36 carbon atoms from the viewpoint of the viscosity index improving effect when used as a viscosity index improver such as lubricating oil. Alkyl (meth)acrylate with branched chain alkyl of 36.

Among these alkyl (meth)acrylates having an alkyl group having 10 to 36 carbon atoms, the viscosity index improving effect when used as a viscosity index improver and the shear viscosity stability when used as a lubricating oil composition From a viewpoint, an alkyl (meth)acrylate having an alkyl group with 14 to 30 carbon atoms is preferred, an alkyl group with 16 to 28 carbon atoms is more preferred, and an alkyl group with 16 to 24 carbon atoms is particularly preferred ( Alkyl meth)acrylates.

The above-mentioned alkyl (meth)acrylates may be used alone or in combination of two or more.

In addition, other (meth)acrylate-based polymerizable monomers other than the aforementioned (meth)acrylate-based polymerizable monomers may be contained in the aforementioned (meth)acrylate-based polymerizable monomers. Examples of the other (meth)acrylate-based polymerizable monomers include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (meth)acrylate (meth)acrylates with alicyclic alkyl groups such as tricyclododecyl acrylate; phenyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, (meth)acrylate (meth)acrylates with aromatic hydrocarbon groups such as biphenyl acrylate; methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-methoxy (meth)acrylate Methoxypropyl, 2-ethoxyethyl (meth)acrylate, 2-ethoxypropyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, (meth) (meth)acrylic esters with ether groups such as methoxypolypropylene glycol acrylate; (meth)N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide , N,N-diisopropyl (meth)acrylamide, N,N-di-n-butyl (meth)acrylamide, etc. N,N-dialkyl (meth)acrylamide; (meth)acrylic acid (meth)acrylates with epoxy groups such as glycidyl esters; 1,3-propanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol Alcohol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate ) acrylate, neopentyl glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate base) acrylate, trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and other multifunctional (meth)acrylates, etc.

In addition, an alkyl (meth)acrylate having an alkyl group having 1 to 9 carbon atoms may be included as the above-mentioned other (meth)acrylate-based polymerizable monomer. As the alkyl (meth)acrylate, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, etc. Alkyl (meth)acrylate with straight chain alkyl of 9; isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isopentyl (meth)acrylate ester, t-amyl (meth)acrylate, isohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate and other branched chains with 3 to 9 carbon atoms Alkyl (meth)acrylate, etc.

The alkyl (meth)acrylate having an alkyl group having 1 to 9 carbon atoms preferably has 1 to 4 carbon atoms from the viewpoint of the viscosity index improving effect when used as a viscosity index improver such as lubricating oil. Alkyl (meth)acrylate of the alkyl group, more preferably methyl (meth)acrylate.

The above-mentioned other (meth)acrylate-based polymerizable monomers may be used alone or in combination of two or more.

As the above-mentioned (meth)acrylate polymerizable monomer, it is preferable to contain a carbon atom-containing Alkyl (meth)acrylates with straight-chain alkyls having a number of 1 to 4, alkyl (meth)acrylates with straight-chain alkyls with 10 to 36 carbon atoms, and branched alkyl (meth)acrylates with 10 to 36 carbon atoms A mixture of alkyl (meth)acrylates with alkyl chains, more preferably methyl (meth)acrylates, alkyl (meth)acrylates with straight-chain alkyls with 12 to 20 carbon atoms, and alkyl (meth)acrylates with carbon A mixture of alkyl (meth)acrylates of branched chain alkyl groups having 16 to 28 atoms.

The above-mentioned (meth)acrylate polymerizable monomer is not particularly limited as long as it contains an alkyl (meth)acrylate having an alkyl group having 10 to 36 carbon atoms, and the viscosity index improvement when used as a viscosity index improver From the viewpoint of effect, the (meth)acrylate-based polymerizable monomer preferably contains 5 to 90% by mass of an alkyl (meth)acrylate having a linear alkyl group having 1 to 4 carbon atoms, and has a carbon number of 5-60% by mass of alkyl (meth)acrylate having a straight-chain alkyl group of 10-36 and 5-60% by mass of alkyl (meth)acrylate having a branched-chain alkyl group having 10-36 carbon atoms The mixture more preferably contains 10 to 60% by mass of methyl (meth)acrylate, 10 to 60% by mass of alkyl (meth)acrylate having a straight-chain alkyl group having 12 to 20 carbon atoms, and 10 to 60% by mass of alkyl (meth)acrylate having 16 carbon atoms. A mixture of 10 to 60% by mass of alkyl (meth)acrylates having branched chain alkyl groups of ~28.

[Compounds having a hydroxyl group in raw materials containing (meth)acrylate-based polymerizable monomers]

In the present invention, in order to obtain a desired (meth)acrylate polymer (A), it is preferable to control the concentration of the compound having a hydroxyl group in the raw material containing a (meth)acrylate polymerizable monomer. As a compound which has a hydroxyl group contained in a raw material, the compound which has water, the compound which has a phenolic hydroxyl group, and the compound which has an alcoholic hydroxyl group (for example, alcohol etc.) is mentioned, for example.

The compound which has a phenolic hydroxyl group is used as a polymerization inhibitor etc. which ensure the storage stability of a (meth)acrylate type polymerizable monomer, for example. Examples of compounds having a phenolic hydroxyl group include hydroquinone, methoxyphenol, p-tert-butylcatechol, 2,4-dimethyl-6-tert-butylphenol, 2,6-tert-butyl- 4-Methylphenol etc. In addition, as a polymerization inhibitor, it is preferable to use hydroquinone, methoxyphenol, and 2,6-t-butyl-4-methylphenol which have a high polymerization inhibitory effect.

As a compound which has an alcoholic hydroxyl group, the alcohol corresponding to the alkyl (meth)acrylate contained in a (meth)acrylate type polymerizable monomer is mentioned, for example. In particular, an alkyl alcohol having an alkyl group having 10 to 36 carbon atoms corresponding to an alkyl (meth)acrylate having an alkyl group having 10 to 36 carbon atoms has a high boiling point and is difficult to contain when contained in the raw material. It is completely removed without affecting the alkyl (meth)acrylate.

The ratio of the compound which has a hydroxyl group in a raw material is preferably 0.2 mass parts or less with respect to 100 mass parts of (meth)acrylate type polymerizable monomers, More preferably, it is 0.1 mass parts or less.

Considering the influence on the production of the (meth)acrylate polymer (A), water is preferably 0.002 parts by mass or less with respect to 100 parts by mass of the (meth)acrylate polymerizable monomer. The compound having an alcoholic hydroxyl group is preferably 0.005 parts by mass or less, and the compound having an alcoholic hydroxyl group is preferably 0.2 parts by mass or less.

In addition, considering the influence on the production of the (meth)acrylate polymer (A) in terms of the ratio of the compound having a hydroxyl group in the raw material, relative to the (meth)acrylate polymerizable monomer 100 parts by mass of water, preferably 0.00001 parts by mass or more of water, preferably 0.00001 parts by mass or more of compounds having phenolic hydroxyl groups, and preferably 0.0001 parts by mass or more of compounds having alcoholic hydroxyl groups.

The reason why the lower limit of water and the compound having an alcoholic hydroxyl group is the above value is that it is difficult to remove more water or a compound having an alcoholic hydroxyl group contained in the raw material from the viewpoint of removal efficiency and economical efficiency. Moreover, the reason why the lower limit of the compound which has a phenolic hydroxyl group is the said value is for ensuring the storage stability of the (meth)acrylate type polymerizable monomer contained in a raw material.

In particular, the alkyl (meth)acrylate having an alkyl group having 10 to 36 carbon atoms contained in the raw material of the (meth)acrylate polymer (A) of the present invention has a high boiling point and usually has the following Tendency: In the raw material containing the alkyl (meth)acrylate, the residual amount of the compound having a hydroxyl group is large.

Content of the compound which has a hydroxyl group contained in the raw material of (meth)acrylate type polymer (A) can be calculated|required by internal standard method or the absolute calibration curve method using gas chromatography or liquid chromatography, for example.

The method for reducing the content of the compound having a hydroxyl group contained in the raw material of the (meth)acrylate polymer (A) is not limited, and examples thereof include polymerization from (meth)acrylate-based polymers by distillation, recrystallization, etc. A method of reducing the content of a compound having a hydroxyl group in a mixture of polymerizable monomers; a method of reducing a compound having a hydroxyl group from a mixture containing a (meth)acrylate-based polymerizable monomer by adsorption treatment using an adsorbent, etc., and further The method etc. which suppress the remaining amount by consuming raw material alcohol at the time of manufacture of a (meth)acrylate type polymerizable monomer are mentioned.

The method of reducing content of the compound which has a hydroxyl group by adsorption process is preferable from the viewpoint of the recovery rate of the raw material containing a (meth)acrylate type polymerizable monomer, and handling simplicity.

As the above-mentioned adsorbent, it can be used without particular limitation as long as it can adsorb and remove the compound having a hydroxyl group. From the viewpoint of high adsorption efficiency, activated alumina, silica, activated clay, acid clay, activated carbon, ion exchange resin, zeolite, Molecular sieve. Among them, activated alumina, zeolite, and molecular sieve are more preferable.

As the method of adsorption treatment, there may be mentioned: a method in which a mixture containing (meth)acrylate polymerizable monomers and an adsorbent are mixed in batches and then stirred or left still; A method of continuously introducing a mixture containing a (meth)acrylate-based polymerizable monomer, and the like.

The adsorption treatment can be performed after diluting the mixture containing the (meth)acrylate polymerizable monomer in a solvent. The solvent used is not particularly limited as long as it does not adversely affect the adsorption treatment, and examples thereof include aliphatic hydrocarbons such as pentane, n-hexane, and octane; cyclopentane, methylcyclopentane, cyclohexane, and the like; Alicyclic hydrocarbons such as alkane, methylcyclohexane, ethylcyclohexane, etc.; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, etc.; diethyl ether, tetrahydrofuran, 1,4-bis Alkanes, anisole, diphenyl ether and other ethers; etc. Among these, aromatic hydrocarbons are preferred, and toluene and xylene are more preferred, from the viewpoints of being able to be directly used in the subsequent polymerization reaction and being easy to recover and purify the solvent. These solvents may be used alone or in combination of two or more.

The mixture to be subjected to the method of reducing the content of the compound having a hydroxyl group may contain two or more (meth)acrylate polymerizable monomers, or may contain only one (meth)acrylate polymerizable monomer. body. As an object for carrying out the above-mentioned method, a mixture containing only one kind of (meth)acrylate-based polymerizable monomer is preferable because it is easy to determine suitable conditions, and it is easy to reduce the compound having a hydroxyl group. Therefore, in the case of using a raw material containing two or more (meth)acrylate polymerizable monomers as the raw material of the (meth)acrylate polymer (A), a preferred mode is to prepare (a (meth)acrylate-based polymerizable monomers containing different types of (meth)acrylate-based polymerizable monomers, and at least one of them is subjected to the method of reducing the content of the compound having a hydroxyl group. After the method, the various mixtures are mixed in such a way as to become the desired state to make the raw material.

[Manufacturing method of mixture containing (meth)acrylate polymerizable monomer]

The method for producing the mixture containing the (meth)acrylate polymerizable monomer used as the raw material of the (meth)acrylate polymer (A) obtained in the present invention is not particularly limited, and known or based methods can be used. to manufacture. Examples include: a method of transesterifying (meth)acrylic acid esters having a short-chain alkyl group such as methyl (meth)acrylate, and an alkyl alcohol in the presence of a Bronsted acid or a Lewis acid catalyst; Method for esterification (condensation) of meth)acrylic acid and alkyl alcohol in the presence of acid catalysts such as sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, solid acid; making (meth)acryloyl chloride or (meth)acrylic acid A method of reacting an anhydride and an alkyl alcohol in the presence of a base such as triethylamine or pyridine, etc.

The mixture containing the (meth)acrylate polymerizable monomer can be obtained from the reaction solution by known methods such as extraction and recrystallization, and the method is not particularly limited. For example, a mixture containing a (meth)acrylate polymerizable monomer derived from a reaction liquid of (meth)acrylic acid and an alkyl alcohol can be obtained by, for example, dissolving (meth)acrylic acid and an alkyl alcohol in toluene, Heating in organic solvents such as alkanes in the presence of acid catalysts such as sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, solid acid, etc., and discharging the generated water out of the system through azeotropic dehydration, while performing the reaction to obtain a reaction solution, and then passing It is obtained by adding an aqueous alkali solution such as sodium hydroxide to the reaction liquid to neutralize and extract the acid catalyst, and then distilling off the solvent in the organic layer.

It is preferable to use a polymerization inhibitor in manufacture of the mixture containing the said (meth)acrylate type polymerizable monomer. As a polymerization inhibitor, for example: quinones such as hydroquinone, methylhydroquinone, and benzoquinone; selected from methoxyphenol, p-tert-butylcatechol, 2,4-dimethyl-6-tert-butyl Compounds having at least one phenolic hydroxyl group among phenol and 2,6-tert-butyl-4-methylphenol; cupferrin, phenothiazine. In addition, as a polymerization inhibitor, it is preferable to use hydroquinone, methoxyphenol, p-tert-butylcatechol, and 2,6-tert-butyl-4-methylphenol which have a high polymerization inhibitory effect.

In terms of the amount of the polymerization inhibitor used in the production of the mixture containing the above-mentioned (meth)acrylate polymerizable monomer, from the viewpoint of preventing the polymerization of (meth)acrylic acid and (meth)acrylate, relative to The total mass of (meth)acrylic acid and alkyl (meth)acrylate used as raw materials is preferably at least 0.001% by mass, more preferably at least 0.005% by mass, and still more preferably at least 0.01% by mass. In addition, from the viewpoint of the usefulness of the product, the amount used is preferably 10% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

Regarding the content of the above-mentioned polymerization inhibitor in the mixture containing the above-mentioned (meth)acrylate-based polymerizable monomer, from the viewpoint of preventing polymerization during storage, relative to the (meth)acrylate-based polymerizable monomer 100 parts by mass, preferably 0.00001 parts by mass or more, more preferably 0.0001 parts by mass or more, still more preferably 0.0005 parts by mass or more. In addition, the content is preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, and still more preferably 0.1 parts by mass or less, from the viewpoint of ease of removal before use during polymerization.

The raw material of (meth)acrylate polymer (A) may be a mixture containing only one (meth)acrylate polymerizable monomer, or may be a mixture containing two or more (meth)acrylate polymerizable monomers. A mixture of monomers. In the case of using a mixture containing two or more (meth)acrylate polymerizable monomers as a raw material, various mixtures containing one or more (meth)acrylate polymerizable monomers can be prepared, and they can be By mixing, it is used as a raw material of (meth)acrylate polymer (A).

[Physical properties of (meth)acrylate polymer (A)]

The weight average molecular weight Mw of the (meth)acrylate polymer (A) of this invention becomes like this. Preferably it is 50,000-500,000, More preferably, it is 100,000-400,000, More preferably, it is 150,000-300,000.

In the (meth)acrylate polymer (A) of the present invention, the ratio of Mw to number average molecular weight (hereinafter referred to as "Mn") (Mw/Mn, hereinafter referred to as "molecular weight distribution") It is preferably 1.6 or less, more preferably 1.01 to 1.6, still more preferably 1.05 to 1.6, particularly preferably 1.05 to 1.5. Using a (meth)acrylate polymer having a molecular weight distribution within such a range provides excellent viscosity index improving effect when used as a viscosity index improver and excellent shear viscosity stability when used as a lubricating oil composition. Mw and Mn depend on, for example, the quantity of the compound which has a hydroxyl group in the raw material containing a (meth)acrylate polymerizable monomer used at the time of manufacture of a (meth)acrylate polymer (A), and a polymerization inhibitor. Mw and Mn are the values of polystyrene conversion molecular weight calculated|required by the said GPC measurement.

In the (meth)acrylate polymer (A) of this invention, content of the structural unit represented by the said General formula (1) becomes like this. Preferably it is 40-80 mass %, More preferably, it is 50-70 mass %. By being within this range, when used as a viscosity index improver, it is easy to dissolve in the base oil even at low temperature.

[Method for producing (meth)acrylate polymer (A)]

The method for producing the (meth)acrylate polymer (A) of the present invention is not particularly limited. In order to make the a value within a desired range, the production method is preferably atom transfer radical polymerization (ATRP), reversible addition fragmentation chain Transfer polymerization (RAFT), nitroxide-mediated polymerization (NMP), iodine transfer polymerization, polymerization using high-period heteroelements (organotellurium, antimony, bismuth, etc.), boron-mediated polymerization, catalytic chain transfer polymerization (CCT), And controllable radical polymerization such as cobalt, titanium and other metals and carbon bonds into dormant species polymerization system (OMRP), and anionic polymerization (representatively highly active anionic polymerization). Among them, anionic polymerization is more preferable because a (meth)acrylate polymer (A) with high thermal stability can be obtained. As the anionic polymerization method, for example, a method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an inorganic acid salt such as an alkali metal or alkaline earth metal salt (see JP-A-7-25859) ; Use an organic alkali metal compound as a polymerization initiator and carry out anionic polymerization in the presence of an organoaluminum compound (refer to Japanese Patent Application Laid-Open No. 11-335432); use organic rare earth metal complexes and metallocene metal complexes as polymerization A method of anionic polymerization with an initiator (see Japanese Patent Application Laid-Open No. 6-93060) and the like.

Among them, from obtaining a polymer with a smaller Mw/Mn, when using it as a viscosity index improver, the shear viscosity stability becomes good, and when using it as a viscosity index improver to obtain a polymer with a high syndiotacticity From the viewpoint of increasing the effect of improving the viscosity index, a method of performing anionic polymerization in the presence of an organoaluminum compound using an organoalkali metal compound as a polymerization initiator is preferable.

A method of anionic polymerization in the presence of an organoaluminum compound using an organoalkali metal compound as a polymerization initiator, which is preferably employed as a method for producing the (meth)acrylate polymer (A), can be carried out, for example, as follows: In the presence of an organolithium compound and an organoaluminum compound represented by the following general formula (2), methyl ether, dimethoxyethane, diethoxyethane, 12-crown ether- 4 and other ethers; triethylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, 1,1 , Nitrogen-containing compounds such as 4,7,10,10-hexamethyltriethylenetetramine, pyridine, and 2,2'-bipyridine are polymerized by polymerizing (meth)acrylate-based polymerizable monomers.

AlR ^a R ^b R ^c (2)

(In the general formula (2), R ^a , R ^b and R ^c independently represent an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, an aryl group that may have a substituent, an aryl group that may have a substituent Aralkyl, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, or an N,N-disubstituted amino group, or R ^a represents any of the aforementioned groups and R ^b and R ^c integrally represent that Arylenedioxy with substituent)

As the organolithium compound used in the above method of performing anionic polymerization, for example, methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, isobutyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, tetramethylenedilithium, pentamethylenedilithium, hexamethylenedilithium and other alkyllithiums and alkyldilithiums; phenyllithium, m-toluene Aryl lithium, p-tolyl lithium, xylyl lithium, naphthyl lithium and other aryl lithium and aryl dilithium; benzyl lithium, diphenylmethyl lithium, trityl lithium, 1,1-diphenyl -Aralkyllithium and aralkyldilithium such as 3-methylpentyllithium, α-methylstyryllithium, dilithium formed by the reaction of diisopropenylbenzene and butyllithium; dimethylamino Lithium, lithium diethylamide, lithium diisopropylamide and other lithium amides; lithium methoxide, lithium ethoxide, lithium n-propoxide, lithium isopropoxide, lithium n-butoxide, lithium sec-butoxide Lithium, lithium tert-butoxide, lithium pentoxide, lithium hexoxide, lithium heptoxide, lithium octoxide, lithium phenoxide, lithium 4-methylphenoxide, lithium benzyloxide, 4-methylphenoxide One or two or more of lithium alkoxides such as lithium benzyloxide.

In addition, as the organoaluminum compound represented by the above general formula (2), for example, trialkylaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-octylaluminum can be used; dimethyl ( 2,6-di-tert-butyl-4-methylphenoxy)aluminum, dimethyl(2,6-di-tert-butylphenoxy)aluminum, diethyl(2,6-di-tert-butyl- 4-methylphenoxy)aluminum, diethyl(2,6-di-tert-butylphenoxy)aluminum, diisobutyl(2,6-di-tert-butyl-4-methylphenoxy) Aluminum, diisobutyl (2,6-di-tert-butylphenoxy) aluminum and other dialkylphenoxy aluminum; methyl bis (2,6-di-tert-butyl-4-methylphenoxy) Aluminum, methylbis(2,6-di-tert-butylphenoxy)aluminum, ethyl[2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum, Ethylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, ethylbis(2,6-di-tert-butylphenoxy)aluminum, ethyl[2,2'- Methylbis(4-methyl-6-tert-butylphenoxy)]aluminum, isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, isobutylbis( 2,6-di-tert-butylphenoxy)aluminum, isobutyl[2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum and other alkyldiphenoxy aluminum; methoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, methoxybis(2,6-di-tert-butylphenoxy)aluminum, methoxy[ 2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum, ethoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum , Ethoxybis(2,6-di-tert-butylphenoxy)aluminum, Ethoxy[2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum , Isopropoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, Isopropoxybis(2,6-di-tert-butylphenoxy)aluminum, Isopropoxy [2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum and other alkoxydiphenoxyaluminum; tris(2,6-di-tert-butyl-4- One or more of triphenoxyaluminum such as methylphenoxy)aluminum, tris(2,6-diphenylphenoxy)aluminum, etc. Among them, isobutylbis(2,6-bis)isobutylbis(2,6-bis tert-butyl-4-methylphenoxy)aluminum, isobutylbis(2,6-di-tert-butylphenoxy)aluminum, isobutyl[2,2'-methylenebis(4-methyl Base-6-tert-butylphenoxy)] aluminum, etc.

The above-mentioned method of carrying out anionic polymerization is preferably carried out in a solvent. The solvent is not particularly limited as long as it does not adversely affect the reaction, and examples include: aliphatic hydrocarbons such as pentane, n-hexane, and octane; cyclopentane, methylcyclopentane, cyclohexane, methylcyclopentane, etc.; Alicyclic hydrocarbons such as hexane and ethylcyclohexane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene; ether, tetrahydrofuran, 1,4-bis Alkanes, anisole, diphenyl ether and other ethers. Among them, aromatic hydrocarbons are preferred, and toluene and xylene are more preferred, from the viewpoints of high solubility of the resulting homopolymer or copolymer, difficulty in mixing into waste water, and ease of recovery and purification of the solvent. These solvents may be used alone or in combination of two or more. It should be noted that, from the viewpoint of smooth progress of the polymerization reaction, the solvent is preferably degassed and dehydrated to be purified in advance.

Moreover, when manufacturing a (meth)acrylate polymer (A), it is preferable to carry out under inert gas atmosphere, such as nitrogen, argon, and helium.

The polymerization temperature at the time of producing the (meth)acrylate polymer (A) may be appropriately selected according to the type of (meth)acrylate to be used, the concentration in the polymerization reaction solution, etc. In the case of production by anionic polymerization in the presence of an initiator and an organoaluminum compound, a temperature in the range of -20 to 80°C is generally preferred because the polymerization time can be shortened and deactivation reactions during polymerization are small. This is an extremely mild temperature condition compared with the anionic polymerization conditions of conventional (meth)acrylate polymerizable monomers. Therefore, when the method of the present invention is implemented industrially, compared with the conventional method, the Cost of cooling equipment.

As a polymerization system for producing a (meth)acrylate polymer (A), a batch polymerization system, a continuous polymerization system, etc. can be used, for example.

The (meth)acrylate polymer (A) can be obtained, for example, by adding a polymerization terminator to the polymerization reaction liquid continuously flowed out from the final reactor for production to terminate the polymerization reaction. As a polymerization terminator, protonic compounds, such as water, methanol, acetic acid, hydrochloric acid, etc. are mentioned, for example. The usage-amount of a polymerization terminator is not specifically limited, Usually, it is the range of 1-100 times mole with respect to the polymerization initiator used.

If aluminum derived from the organoaluminum compound used remains in the (meth)acrylate polymer (A) separated from the polymerization reaction liquid after the completion of the polymerization, the (meth)acrylate polymer may (A) Since the physical properties of the material using it deteriorate, it is preferable to remove aluminum derived from the organoaluminum compound after the polymerization is completed. As the method for removing the aluminum, a method of washing the polymerization reaction liquid after adding a polymerization terminator with an acidic aqueous solution, a method of subjecting it to adsorption treatment using an adsorbent such as an ion exchange resin, etc. are effective.

There are no particular limitations on the method for isolating and obtaining the (meth)acrylate polymer (A) from the polymerization reaction solution after the polymerization was terminated and the aluminum removal treatment was performed, and known methods can be appropriately used. Examples include: injecting the polymerization reaction solution into a poor solvent for the (meth)acrylate polymer (A) to precipitate the (meth)acrylate polymer (A); The method etc. which distill off a solvent under reduced pressure and obtain a (meth)acrylate polymer (A). In addition, it is also possible to remove most of the solvent and low-boiling point components from the polymerization reaction liquid first by using a thin film evaporator or the like, and then continuously supply the obtained residue to a melt extruder in which The solvent etc. were distilled off under pressure, and the (meth)acrylate polymer (A) was collect|recovered as a strand, a pellet, or a cake-like mass. In addition, it may be taken out as a polymerization reaction liquid, or may be taken out as a solution dissolved in a solvent different from the solvent used for polymerization by adding a solvent having a higher boiling point than the solvent used and removing the solvent.

The (meth)acrylate polymer (A) of the present invention may be a homopolymer produced from a single monomer or may be a copolymer produced from a plurality of monomers. As a homopolymer, it may be linear or star-shaped. The copolymer may be a random copolymer, a block copolymer, a graft copolymer, or a star copolymer.

To the (meth)acrylate polymer (A) of the present invention, antioxidants, thermal deterioration inhibitors, light stabilizers, ultraviolet absorbers, lubricants, release agents, polymer processing aids, antistatic Agents, flame retardants, dyes and pigments, light diffusing agents, organic pigments, matting agents, impact modifiers, phosphors, antiwear agents (or extreme pressure agents), corrosion inhibitors, rust inhibitors, viscosity index improvers , pour point depressant, demulsifier, metal deactivator, defoamer, ashless friction modifier and other additives before use.

The (meth)acrylate polymer (A) of the present invention has excellent mechanical properties such as narrow molecular weight distribution and shear viscosity stability, so it can be used not only for viscosity index improvers, but also for polyolefin modification. Various applications such as surface functional coating agents, adhesives, adhesives, primers, hard coats, and tire modifiers. Particularly preferably, it can be used as a viscosity index improver because it has high solubility in engine oil and can reduce the temperature dependence of the viscosity of engine oil.

Example

Hereinafter, the present invention will be described more specifically by way of examples and comparative examples, but the present invention is not limited by the following examples. In addition, the measurement of a physical property value etc. was implemented by the following method.

(Content of (meth)acrylate polymerizable monomer, content of compound having phenolic hydroxyl group, content of compound having alcoholic hydroxyl group)

InertCap 1 (df = 0.4 μm, 0.25 mm I.D. x 60 m) manufactured by GL Sciences Inc. was connected as a column to a gas chromatograph GC-2014 manufactured by Shimadzu Corporation, and the injection temperature was set to 240° C. The temperature was set to 300° C., and the column temperature was raised from 180° C. to 280° C. at a temperature increase rate of 10° C./minute, and then measured for 10 minutes. The purity of the (meth)acrylate polymerizable monomer is calculated from the simple area (simple area) detected in gas chromatography, and the content of the compound with phenolic hydroxyl group and the compound with alcoholic hydroxyl group is determined by the absolute calibration curve method. Calculated as a mass ratio with respect to 100 parts by mass of the monomer.

(moisture content in raw material)

The amount of moisture in the monomer was measured using a volumetric Karl Fischer moisture meter CA-200 manufactured by Mitsubishi Chemical Analytic Inc., and calculated as a mass ratio to 100 parts by mass of the monomer.

(weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw/Mn))

Gel permeation chromatography (GPC) measurement was performed under the following conditions, and the values of Mw, Mn, and Mw/Mn in terms of molecular weight of standard polystyrene were calculated from the obtained chromatogram. It should be noted that the baseline was set at the point where the slope of the peak on the high molecular weight side of the GPC chart was changed from zero to positive when viewed from the side with the earlier retention time and the point at which the peak at the lower molecular weight side was observed from the side with the earlier retention time. A line connecting points where the slope changes from negative to zero.

GPC device: Tosoh Corporation make, HLC-8320

Detector: Differential Refractive Index Detector

Column: A column in which two TSKgel SuperMultipore HZM-M manufactured by Tosoh Corporation and SuperHZ4000 were connected in series was used.

Eluent: tetrahydrofuran

Eluent flow rate: 0.35ml/min

Column temperature: 40°C

Standard curve: made using 10-point standard polystyrene data

(monomer composition in polymer)

Using a nuclear magnetic resonance apparatus (ULTRA SHIELD 400PLUS manufactured by Bruker Co.), 10 mg of the resin was measured in ¹ mL of deuterated chloroform, room temperature, and 64 accumulation times. From this spectrum, TMS was set to 0 ppm. The area value of the signal from the methylene group, methine group, and methyl group adjacent to the oxygen atom of the ester group at 3.3 to 4.2 ppm is calculated from the monomer in the (meth)acrylate polymer (A) composition of structural units.

(Manufacturing example 1)

In a 500-mL three-neck flask equipped with a thermometer, a distillation column (2 cm in inner diameter, 25 cm in length) filled with a glass Raschig ring, and a glass capillary, was added a mixture containing 2-octyldodecanol and methacrylic acid. A mixture of 2-octyldodecyl methacrylate ((meth)acrylate-based polymerizable monomer) (2-octyldodecyl methacrylate 98.67%; relative to methacrylic acid 2 -Based on 100 parts by mass of octyl dodecyl ester, 0.0101 parts by mass of methoxyphenol, 0.2533 parts by mass of 2-octyldodecyl alcohol and 0.0203 parts by mass of water) 455 g, ADK STABAO as a polymerization inhibitor- 60 (compound with phenolic hydroxyl group: manufactured by ADEKA Co., Ltd.) 0.46 g, while blowing air from a glass capillary, while passing 18 hours at an internal pressure of 0.1 kPa, an internal temperature of 214 to 234°C, and a tower top temperature of 185 to 191°C The distillate was divided into about 70 g and distilled. Among these, the fraction with little content of 2-octyldodecanol and methoxyphenol was used as the raw material of (meth)acrylate polymer (A), and 82.1 g (18.0% of recovery rate) of raw materials (1) were obtained. As a result of measurement by gas chromatography and a Karl Fischer moisture meter, the content of 2-octyldodecyl methacrylate in the raw material (1) of the (meth)acrylate polymer (A) 99.54%, with respect to 100 parts by mass of (meth)acrylate-based polymerizable monomers, the content of water was 0.0007 parts by mass, the content of 2-octyldodecanol was 0.017 parts by mass, and methoxyphenol was not detected and ADKSTABAO-60.

(Manufacturing example 2)

Add a mixture containing n-stearyl methacrylate ((meth)acrylate-based polymerizable monomer) synthesized by esterification of n-stearyl alcohol and methacrylic acid to a 1L three-necked flask equipped with a thermometer and a mechanical stirrer (99.26% of n-stearyl methacrylate; based on the content of 100 parts by mass of n-stearyl methacrylate, it contains 0.0252 parts by mass of methoxyphenol, 0.3425 parts by mass of n-stearyl alcohol and 0.0181 parts by mass of water) 250 g and 583 g of isopropyl alcohol were stirred at 25°C to dissolve n-stearyl methacrylate. Then, it cooled to -20 degreeC over 4 hours. The precipitated crystal was filtered and dried to obtain 243.3 g (97.3% of recovery) of the raw material (2) of the crystalline (meth)acrylate polymer (A). As a result of measuring by gas chromatography and Karl Fischer moisture meter, in the raw material (2) of (meth)acrylate polymer (A), the content of n-stearyl methacrylate is 99.67%, which is relatively The content of water was 0.001 parts by mass and the content of n-stearyl alcohol was 0.006 parts by mass based on 100 parts by mass of (meth)acrylate-based polymerizable monomers, and methoxyphenol was not detected.

(Manufacturing example 3)

In the 500mL three-neck flask that has put into magnetic stirring bar, add the 2-octyl dodecyl methacrylate ((meth)acrylic acid ester that contains by the esterification synthesis of 2-octyl dodecyl alcohol and methacrylic acid polymerizable monomer) (98.67% of 2-octyldodecyl methacrylate; based on the content of 100 parts by mass of 2-octyldodecyl methacrylate, containing 90 g of 0.0101 parts by mass of phenol, 0.2533 parts by mass of 2-octyldodecanol, and 0.0203 parts by mass of water), 210 g of toluene, and 30 g of activated alumina GP-20 manufactured by Mizusawa Chemical as an adsorbent were stirred at 25° C. for 4 hours. Then, activated alumina was removed by filtration, and toluene was distilled off at a liquid temperature of 35° C. or lower with an evaporator to obtain 86.1 g of a raw material (3) of a liquid (meth)acrylate polymer (A). As a result of measuring by gas chromatography and Karl Fischer moisture meter, the content of 2-octyldodecyl methacrylate in the raw material (3) of (meth)acrylate polymer (A) 98.88%, with respect to 100 parts by mass of (meth)acrylate-based polymerizable monomers, the content of water was 0.0006 parts by mass, the content of 2-octyldodecanol was 0.14 parts by mass, and no methoxyphenol was detected .

(Manufacturing example 4)

In the 500mL three-neck flask that has put into magnetic stirring bar, add the mixture containing the n-stearyl methacrylate ((meth)acrylate polymerizable monomer) synthesized by the esterification of n-stearyl alcohol and methacrylic acid ( 99.26% of n-stearyl methacrylate; based on the content of 100 parts by mass of n-stearyl methacrylate, it contains 0.0252 parts by mass of methoxyphenol, 0.3425 parts by mass of n-stearyl alcohol and 0.0181 parts by mass of water) 90g , 210 g of toluene, and 30 g of activated alumina GP-20 manufactured by Mizusawa Chemical Co., Ltd. as an adsorbent were stirred at 25° C. for 4 hours. Then, activated alumina was removed by filtration, and toluene was distilled off at a liquid temperature of 35° C. or lower with an evaporator to obtain 87.2 g of a raw material (4) of a liquid (meth)acrylate polymer (A). As a result of measuring by gas chromatography and a Karl Fischer moisture meter, the content of n-stearyl methacrylate in the raw material (4) of the (meth)acrylate polymer (A) was 99.20%. The content of water was 0.0007 parts by mass and the content of 2-stearyl alcohol was 0.11 parts by mass based on 100 parts by mass of (meth)acrylate-based polymerizable monomers, and methoxyphenol was not detected.

(Manufacturing example 5)

To the raw material (3) containing 2-octyl dodecyl methacrylate obtained in Production Example 3, the amount was 0.0005 parts by mass relative to 100 parts by mass of the (meth)acrylate-based polymerizable monomer The raw material (5) of the (meth)acrylate polymer (A) was prepared by adding p-methoxyphenol.

(Manufacturing example 6)

To the n-stearyl methacrylate-containing raw material (4) obtained in Production Example 4, p-methoxy was added so as to reach 0.0005 parts by mass relative to 100 parts by mass of the (meth)acrylate-based polymerizable monomer. Phenol, thereby preparing the raw material (6) of the (meth)acrylate polymer (A).

(Manufacturing example 7)

In the raw material (3) containing 2-octyldodecyl methacrylate obtained in Production Example 3, the amount was adjusted to 0.32 parts by mass relative to 100 parts by mass of the (meth)acrylate-based polymerizable monomer The raw material (7) of the (meth)acrylate polymer (A) was prepared by adding 2-octyldodecanol.

(Manufacturing example 8)

To the n-stearyl methacrylate-containing raw material (4) obtained in Production Example 4, n-stearyl alcohol was added so as to be 0.36 parts by mass relative to 100 parts by mass of the (meth)acrylate-based polymerizable monomer , thereby preparing the raw material (8) of the (meth)acrylate polymer (A).

<Example 1>

Referring to JP-A-2007-84658, the (meth)acrylate polymer was produced as follows. After replacing the inside of the fully dried 2L three-necked flask with nitrogen, 480 g of toluene, 24 g of 1,2-dimethoxyethane, isobutylbis(2,6-di-tert-butyl - 10 g of a 0.45M toluene solution of 4-methylphenoxy)aluminum, and 0.62 g of a mixed solution of cyclohexane and n-hexane containing 1.0 mmol of sec-butyllithium was further added. Next, 30 mass % of the raw material (1) obtained in Production Example 1 containing 2-octyldodecyl methacrylate as a (meth)acrylate-based polymerizable monomer was mixed with 30% by mass in Production Example 2. Synthesized raw material (2) 30% by mass obtained in Production Example 2 containing stearyl methacrylate as a (meth)acrylate-based polymerizable monomer and methyl methacrylate raw material (manufactured by Kuraray Co., Ltd.: The content of methyl methacrylate is 99.9% or more; with respect to 100 parts by mass of methyl methacrylate, the content of water is 0.0003 parts by mass, the content of methanol is 0.0002 parts by mass or less, and 2,4-dimethyl- 6-tert-butylphenol content: 0.0001 parts by mass) 40 mass % mixture as a raw material (with respect to 100 parts by mass of (meth)acrylate polymerizable monomers, the content of alcohol is 0.0070 parts by mass, the content of water is 0.0006 parts by mass , the content of the compound having a phenolic hydroxyl group is below the detection limit), 85 g was added, and stirred at room temperature for 12 hours. The reaction solution was initially colored yellow, but became colorless after stirring for 12 hours. Then, 1.0 g of methanol was added to terminate the polymerization reaction. The obtained reaction liquid was poured into 6.0 kg of methanol to deposit a white precipitate. Then, 80 g of methacrylate polymers were obtained by collecting this white deposit by filtration and drying.

As a result of ¹ H-NMR measurement and GPC measurement of the obtained methacrylate polymer, it was a random copolymer with a weight average molecular weight (Mw) of 81800, a number average molecular weight (Mn) of 75600, and a molecular weight distribution ( Mw/Mn) was 1.08.

In addition, it was found that the mass ratio of the structures derived from each monomer in the obtained methacrylate polymer was 40% by mass of the structure derived from methyl methacrylate and 30% by mass of the structure derived from stearyl methacrylate. % by mass, and the structure derived from 2-octyldodecyl methacrylate was 30% by mass. The results are shown in Table 1.

<Example 2>

0.62 g of a mixed solution of cyclohexane and n-hexane containing 1.0 mmol of sec-butyllithium was changed to 0.39 g of a mixed solution of cyclohexane and n-hexane containing 0.64 mmol of sec-butyllithium, and the same as Example 1 except that By operation, 80 g of a methacrylate polymer was obtained. Table 1 shows the evaluation results of the obtained methacrylate polymer.

<Example 3>

0.62 g of a mixed solution of cyclohexane and n-hexane containing 1.0 mmol of sec-butyllithium was changed to 0.33 g of a mixed solution of cyclohexane and n-hexane containing 0.55 mmol of sec-butyllithium, and the same as in Example 1 except that By operation, 80 g of a methacrylate polymer was obtained. Table 1 shows the evaluation results of the obtained methacrylate polymer.

<Example 4>

0.62 g of a mixed solution of cyclohexane and n-hexane containing 1.0 mmol of sec-butyllithium was changed to 0.27 g of a mixed solution of cyclohexane and n-hexane containing 0.44 mmol of sec-butyllithium, and the same as in Example 1 except that By operation, 80 g of a methacrylate polymer was obtained. Table 1 shows the evaluation results of the obtained methacrylate polymer.

<Example 5>

0.62 g of a mixed solution of cyclohexane and n-hexane containing 1.0 mmol of sec-butyllithium was changed to 0.25 g of a mixed solution of cyclohexane and n-hexane containing 0.41 mmol of sec-butyllithium, and the same as in Example 1 except that By operation, 80 g of a methacrylate polymer was obtained. Table 1 shows the evaluation results of the obtained methacrylate polymer.

<Example 6>

Instead of the raw material used in Example 3, 30 wt. %, 30% by mass of the raw material (4) obtained in Production Example 4 containing stearyl methacrylate as a (meth)acrylate-based polymerizable monomer and methyl methacrylate raw material (manufactured by Kuraray Co., Ltd.: The content of methyl methacrylate is 99.9% or more; with respect to 100 parts by mass of methyl methacrylate, the content of water is 0.0003 parts by mass, the content of methanol is 0.0002 parts by mass or less, and 2,4-dimethyl- 6-tert-butylphenol content: 0.0001 parts by mass) 40 mass % mixture as a raw material (with respect to 100 parts by mass of (meth)acrylate polymerizable monomers, the content of alcohol is 0.0751 parts by mass, the content of water is 0.0005 parts by mass , content of the compound which has a phenolic hydroxyl group is below the detection limit), except having added 85 g, it carried out similarly to Example 3, and obtained 80 g of methacrylate polymers. Table 1 shows the evaluation results of the obtained methacrylate polymer.

<Example 7>

Instead of the raw material used in Example 3, 30 wt. %, 30% by mass of the raw material (6) obtained in Production Example 6 containing stearyl methacrylate as a (meth)acrylate polymerizable monomer and methyl methacrylate raw material (manufactured by Kuraray Co., Ltd.: The content of methyl methacrylate is 99.9% or more; with respect to 100 parts by mass of methyl methacrylate, the content of water is 0.0003 parts by mass, the content of methanol is 0.0002 parts by mass or less, and 2,4-dimethyl- 6-tert-butylphenol content: 0.0001 parts by mass) 40 mass % mixture as a raw material (with respect to 100 parts by mass of (meth)acrylate polymerizable monomers, the content of alcohol is 0.0751 parts by mass, the content of water is 0.0005 parts by mass , content of 0.0003 mass parts of the compound which has a phenolic hydroxyl group), except having added 85 g, it carried out similarly to Example 3, and obtained 80 g of methacrylate polymers. Table 1 shows the evaluation results of the obtained methacrylate polymer.

＜Comparative example 1＞

Instead of the raw material used in Example 5, a mixture containing 2-octyldodecyl methacrylate synthesized by esterification of 2-octyldodecanol and methacrylic acid (2-octyl methacrylate The content of dodecyl ester is 98.67%; based on the content of 100 parts by mass of 2-octyldodecyl methacrylate, it contains 0.0101 parts by mass of methoxyphenol and 0.2533 parts by mass of 2-octyldodecyl alcohol and water 0.0203 parts by mass) 35 mass %, containing the mixture of n-stearyl methacrylate synthesized by the esterification of n-stearyl alcohol and methacrylic acid (n-stearyl methacrylate content 99.26%; 0.0252 parts by mass of methoxyphenol, 0.3425 parts by mass of n-stearyl alcohol and 0.0181 parts by mass of water) and 35 mass % of methyl methacrylate raw materials (manufactured by Kuraray Co., Ltd.) based on 100 parts by mass of n-stearyl acrylate : The content of methyl methacrylate is 99.9% or more; the content of water is 0.0003 parts by mass and the content of methanol is 0.0002 parts by mass or less; 2,4-dimethyl as a polymerization inhibitor is 100 parts by mass of methyl methacrylate - 6-tert-butylphenol content: 0.0001 parts by mass) 30 mass % mixture as a raw material (with respect to 100 parts by mass of (meth)acrylate polymerizable monomers, the content of alcohol is 0.2066 parts by mass, the content of water is 0.0134 mass parts 80 g of methacrylate polymers were obtained in the same manner as in Example 5 except that 85 g was added to the content of the compound having a phenolic hydroxyl group (0.0123 parts by mass). Table 1 shows the evaluation results of the obtained methacrylate polymer.

＜Comparative example 2＞

Instead of the raw material used in Example 3, 30 wt. %, 30% by mass of the raw material (8) obtained in Production Example 8 containing stearyl methacrylate as a (meth)acrylate polymerizable monomer synthesized in Production Example 8 and methyl methacrylate raw material ( Manufactured by Kuraray Co., Ltd.: 99.9% or more of methyl methacrylate; 0.0003 parts by mass of water and 0.0002 parts by mass of methanol per 100 parts by mass of methyl methacrylate; 2, 4-dimethyl-6-tert-butylphenol content 0.0001 mass parts) 40 mass % of the mixture as a raw material (with respect to (meth)acrylate polymerizable monomer 100 mass parts, alcohol content 0.2041 mass parts, Content of water 0.0005 mass parts, content of the compound which has a phenolic hydroxyl group is below a detection limit) and 85 g were added, and it carried out similarly to Example 3, and obtained 80 g of methacrylate polymers. Table 1 shows the evaluation results of the obtained methacrylate polymer.

＜Comparative example 3＞

Referring to Synthesis Example 3 of JP-A-2015-013964, a methacrylate polymer was produced as follows. A stirring blade, a serpentine condenser, and a three-way valve were installed in a fully dried 2 L three-necked flask, and after the inside was replaced with nitrogen, at room temperature, the mixture containing as (methyl) Raw material (3) 30% by mass of 2-octyldodecyl methacrylate as an acrylate-based polymerizable monomer, methacrylate as a (meth)acrylate-based polymerizable monomer obtained in Production Example 4 Stearyl acrylate raw material (4) 30% by mass and methyl methacrylate raw material (manufactured by Kuraray Co., Ltd.: the content of methyl methacrylate is 99.9% or more; relative to 100 mass parts of methyl methacrylate, water content of 0.0003 parts by mass, the content of methanol below 0.0002 parts by mass, the content of 0.0001 parts by mass of 2,4-dimethyl-6-tert-butylphenol as a polymerization inhibitor) 40 mass % mixture as raw material (relative to ( 100 parts by mass of meth)acrylate-based polymerizable monomers, 0.07508 parts by mass of alcohol, 0.0051 parts by mass of water, and 500 g of compounds having phenolic hydroxyl groups below the detection limit), and then highly purified minerals 500 g of oil and 0.53 g of cumyl dithiobenzoate (CDTBA) were prepared into a homogeneous solution under stirring. The solution was cooled to 0°C with an ice bath, and the reaction system was vacuum degassed/nitrogen purged five times with a diaphragm pump. Further, after 0.0083 g of azobisisobutyronitrile (AIBN) as a free radical initiator was dropped from the sample introduction port under a nitrogen flow, polymerization was carried out at a solution temperature of 90° C. under a nitrogen atmosphere for 12 hours to obtain polymer solution. Table 1 shows the evaluation results of the obtained methacrylate polymer.

＜Comparative example 4＞

Referring to Example 1 of Japanese Patent No. 4681187, a methacrylate polymer was produced as follows. A stirring blade, a serpentine condenser, and a three-way valve were installed in a fully dried 2 L three-necked flask, and after the inside was replaced with nitrogen, at room temperature, the mixture containing as (methyl) Raw material (3) 30% by mass of 2-octyldodecyl methacrylate as an acrylate-based polymerizable monomer, methacrylate as a (meth)acrylate-based polymerizable monomer obtained in Production Example 4 Stearyl acrylate raw material (4) 30% by mass and methyl methacrylate raw material (manufactured by Kuraray Co., Ltd.: the content of methyl methacrylate is 99.9% or more; relative to 100 mass parts of methyl methacrylate, water content of 0.0003 parts by mass, the content of methanol below 0.0002 parts by mass, the content of 0.0001 parts by mass of 2,4-dimethyl-6-tert-butylphenol as a polymerization inhibitor) 40 mass % mixture as raw material (relative to ( 100 parts by mass of meth)acrylate-based polymerizable monomers, 0.07508 parts by mass of alcohol, 0.0051 parts by mass of water, and 500 g of compounds having phenolic hydroxyl groups below the detection limit), and further highly purified minerals 500 g of oil was inertized by passing nitrogen gas. Next, 0.18 g of CuBr and 0.22 g of a ligand (pentamethyldiethylenetriamine (PMDETA)) were added as a catalyst, respectively. After heating to 90°C, 0.45 g of an initiator (ethyl 2-bromoisobutyrate) was added. The temperature in the three-necked flask was raised to 100° C., polymerization was implemented for 20 hours, and a solution containing a methacrylate polymer was obtained. Table 1 shows the evaluation results of the obtained methacrylate polymer.

The methacrylate polymers of Examples 1 to 7 were all well dissolved in the base oil, and the shear viscosity was lower than that of the methacrylate polymers of Comparative Examples 1 to 4 whose a values exceeded the stipulations of the present invention. Excellent stability.

Claims (5)

1. a kind of (methyl) acrylic ester polymer (A), contains the structural unit represented by the following general formula (1), wherein It is obtaining, polystyrene conversion to be somebody's turn to do being measured by gel permeation chromatography (GPC) for (methyl) acrylic ester polymer (A) The intensity of peak top molecular weight M (t) is standardized as in the 1 differential molecular weight distribution curve of polystyrene conversion molecular weight, The polystyrene conversion molecular weight of the high molecular weight side for the position that intensity is 0.5 is set as M_h(t_1/2) when, following formula (2) institute table The a values shown be 0.12 hereinafter,

In formula (1), R¹Indicate hydrogen atom or methyl, R²Indicate that carbon atom number is 10~36 alkyl,

A=Log M_h(t_1/2)-Log M(t) (2)。

2. (methyl) acrylic ester polymer (A) according to claim 1, wherein differential described in claim 1 In molecular weight distribution curve, the polystyrene conversion molecular weight in the low molecular weight side for the position for being 0.5 by intensity is set as M_l (t_1/2) when, half-peak breadth LogM_h(t_1/2)-LogM_l(t_1/2) it is 0.3 or less.

3. (methyl) acrylic ester polymer (A) according to claim 1 or 2, wherein the general formula (1) is represented Structural unit relative to composition (methyl) acrylic ester polymer (A) entire infrastructure unit quality content be 40~ 80 mass %.

4. (methyl) acrylic ester polymer (A) described in any one of claim 1 to 3, wherein wanted by right The polystyrene conversion weight average molecular weight Mw for asking the GPC described in 1 to measure and calculating is 50000~500000.

5. the manufacturing method of (methyl) acrylic ester polymer (A) according to any one of claims 1 to 4, it makes use of Anionic polymerization in the presence of organo-aluminum compound.